Your Basement Is a Lot Like a Cave: Managing Summertime Humidity

Not everyone has been in a cave, but a lot of us probably visited one as a kid—maybe Mammoth Cave or someplace similar. And even if you haven’t, almost everybody in Cincinnati has experienced that cold, damp feeling when you walk into a basement in the middle of summer.

There’s a reason for that.

Your basement is actually a lot like a cave. It’s mostly below ground, usually doesn’t have many windows, doesn’t get much natural airflow, and the surrounding earth keeps it cooler than the outside air.

During a Cincinnati summer, warm humid air finds its way into that cooler basement. As that air cools, the relative humidity rises. Add in moisture that may be moving through an older foundation, and you can end up with a basement that feels damp and smells musty even though you don’t see any standing water.

Older homes can be especially susceptible. Exterior foundation coatings, drainage systems, gutters, grading and other methods of managing water may not work as well as they once did.

Finishing a Basement Doesn’t Fix the Humidity

Here in Cincinnati, we have a lot of homes where basements have been turned into really nice living spaces. We frame the walls, hang drywall, install flooring and suddenly the basement becomes a family room, playroom, home office or a place to watch TV.

But drywall and flooring don’t change the environment.

If you’re going to turn a basement into living space, controlling humidity is just as important as making it look good.

High humidity can slowly damage building materials and create conditions where mold and mildew can grow. That can lead to musty odors, damaged finishes and a basement that nobody really wants to spend time in.

The good news is that humidity is usually much less expensive to manage before it causes damage.

A Dehumidifier and Air Movement Can Make a Big Difference

For many of the basements I see, two simple things can help tremendously: a good dehumidifier and some air movement.

Dehumidifiers come in all different types. Some have digital controls that allow you to select a specific humidity level. Others simply have a dial that runs from more dry to less dry.

Personally, I find that basement areas tend to do well when the relative humidity is kept somewhere in the 40% range. You don’t necessarily need to make the basement bone dry—you just want to keep humidity under control and prevent the space from staying damp for long periods.

I also like some air movement.

In my own basement, I run a small fan. It helps circulate the air through the space, helps the dehumidifier work on air throughout the room, and keeps those stagnant areas behind furniture and in corners from staying damp.

That doesn’t mean a fan or dehumidifier will solve an actual water-infiltration problem. If you have water coming through the foundation, a plumbing leak, poor exterior drainage or another source of bulk water, you need to find and correct that problem.

But for normal summertime basement humidity, these are two inexpensive tools that can make a noticeable difference.

Manage Moisture Before It Becomes Damage

This is something I see over and over again in remodeling and repair work: a relatively inexpensive maintenance issue gets ignored until it becomes a much more expensive repair.

Basement humidity is a good example.

A dehumidifier, a small fan and a little attention to the humidity level can cost very little compared with replacing mold-damaged drywall, trim, flooring or furnishings later.

So if your basement starts getting that familiar cold, damp, musty summertime feeling, don’t just assume that’s what basements are supposed to smell like.

Give the dehumidifier and some air movement a try.

You may find that your basement feels a lot less like a cave—and a lot more like part of your home.

All the best,

Birch Bishop
Mariemont Remodeling Co.
Serving Mariemont and the surrounding villages since 1940